We're still hoping that we're seeing positive results by ensuring that the efi and smc are up to date and then reimaging.

For reference, these appear to be the latest:

Late 2012 iMac13,1
Boot rom IM131.010A.B09
SMC 2.9f8

Late 2013
iMac14,3
Boot rom IM143.0118.B13
SMC 2.17f7

We've imaged pretty much imaged all of them over the 2.5 weeks and so far haven't seen the issue again on any, having made sure we did the firmware update first.

Can anyone else confirm if they're seeing the issue on machines with up to date firmware?

Just to chime in here, we are experiencing this issue as well. We have 6 x iMac Intel (21.5-Inch, Late 2015) 16,1 w/ firmware passwords all running 10.11.6 in our Middle School. We are not running the latest security updates on these machines. They are running SMC 2.31f36 ; Boot ROM IM161.0207.B03

I've been looking at our system logs and I'm seeing a lot of forced shutdowns and power disconnects. We actually saw several of our students unplugging the power from these machines.

Going over the thread though it appears my initial thought that these improper shutdowns were the cause are in fact symptoms of a larger problem. As of yet, we haven't seen this issue on any of other iMacs or Mac computers.

I put a ticket in with Apple through my GSX account and uploaded a log file from a troubled machine. They get back to me 4 days later and say:

There is nothing hardware related that stood out after review of the log files attached, however if you are still having the issue in a a clean known good OS, please initiate a technical support chat if you do require any further assistance troubleshooting the issue.

Thanks Apple

So far ours have been looking ok. I've now added the EFI/SMC update to the imaging workflow and tested it in a few places and it successfully updates the mac before it boots into the OS for the first time.

We've still got a few machines with the issue but these were imaged about 3 weeks ago and were prior to the firmware update.

We're still kinda of pinning all our hopes on the firmware update then a reimage fixing it but sadly only time will tell.

As expected Apple's reply is useless and I'm sure their "fix" will just to be to update to Sierra which of course is really simple...

Has anyone actually logged a ticket with Jamf about it other that post on this thread? I'm not classing this as a Casper issue as I think the boot issue kicks in long before anything Casper related is loaded but it might be interesting to hear their take on it.

@allanp81 I was going to try and give the upgrade a try on at least one machine this week.

I also found this thread from Apple's threads back from February about an hp_io_enabler_compound.kext preventing startup. In our environment this appears to be the only Apple kext on our computers, so I was also going to try messing with this as well.

@aporlebeke I'd be very surprised if that kext has anything to do with.

We've just had a few of us do it again, although they had their firmware updates done after they were last imaged.

The most recent time these were imaged was the 8th of November. We've reimaged them again and will see.

@aporlebeke @allanp81 I was seeing huge issues in carts of MacBook Airs and also iMacs / Mac Minis. These machines were running Operating System Build: 15G31

After I created a new image with all patches / security updates the new build is Operating System Build: 15G1108

Since creating a new image and re-deploying things have been quiet.

@Chuey How long ago were they imaged?

@allanp81 I piloted this image to 1 cart of 30 MacBook Airs that were having major issues about 3 weeks ago. Since imaging that cart not 1 peep from them.

I just re-imaged 5 carts of 30 MacBook Airs on Wednesday and Friday of last week.

@Chuey If you're going to see the issue then it would be any day based on our experiences here.

@allanp81 Are you using Operating System Build: 15G1108 and still seeing the issue?

@Chuey No we're still using 10.11.5 as our base image. We did manually update some of the machines to 10.11.6 when we first started seeing the issues but it didn't seem to help, they were still randomly getting stuck on boot.

Just chiming in here to report that we are having the same exact issue. High usage area, common lab, lots of user accounts. It is all iMacs in our environment (Retina 5K, Late-2014, Running 10.11.6, 1TB Hybrid drives).

In our environment repetitive single-user or verbose boots will eventually get them to boot. I've looked very closely at the verbose logs and I'm not really seeing any red flags. There is this which shows up almost every time, seems it can't delete the dyld caches.

Oct 11 16:19:17 localhost kernel[0]: Sandbox: launchd(1) System Policy: deny(1) file-write-unlink /private/var/run/dyld_shared_cache_x86_64h Oct 11 16:19:17 localhost com.apple.xpc.launchd[1]: Failed to remove file or directory: name = dyld_shared_cache_x86_64h, error = 1: Operation not permitted. Further logging suppressed. When it stalls in verbose boot it tends to stall right after "SDXC: pause". System.log shows this coming up after that (not displayed in Verbose boot) Oct 11 16:17:45 localhost kernel[0]: Sandbox: launchd(1) System Policy: deny(1) file-write-unlink /private/var/run/dyld_shared_cache_x86_64h.map

I re-imaged the entire lab about ~1 month ago and just now the issue started cropping up again. We deploy lots of Adobe CC apps, as well as Office 16. I do have quite a lot of unofficial kext's loading - that will be my next thing to look at.

My other thought was that it could be related to the Hybrid drives in some way, but I have no evidence for that. Just know how much we've struggled deploying to them or having them 'unfuse' themselves. Maybe firmwmare related to CoreStorage?

Eager to hear if Apple has responded with anything useful - it's getting to be the end of the semester and we really can't have this many machines out of order.

@kayzlot1 The machines we've seen the issue originally had fusion drives in them but were all upgraded with Samsung 850 Pro SSDs. On some machines the Apple SSD portion of the fusion drive is still present but not on all of them (I guess different people did the upgrades?). The drives are separate though, they haven't been "joined" with the new drives.

We also deploy Adobe CC and Office 2016.

We too see the same errors about the dyld caches that you're seeing but I couldn't find anything useful as to what this meant and also how to fix it.

@kayzlot1 Can you tell me what Operating System Build version you are using to image your machines with?

Has anyone tried:

sudo update_dyld_shared_cache -force

In theory that could be run from single user mode.

Holding down shift on boot will also clear this cache at the same time as performing a safe boot.

@Chuey 15G31
Edit: Should clarify, that's the original image. Post-deploy after all security updates applied they are sitting on 15G1108.

@allanp81 I'm pretty sure iMac's have a mini-PCIE or m.2 SSD that works in conjunction with the standard SATA hard drive. Sounds like whoever did the installs forgot to pull the SSDs.

@kayzlot1 Ok, I used the latest Install.app and AutoDMG to create our image. I applied all updates to the image before compiling this way it was up to date before I shipped it out to computers.

I'm not 100% positive or anything but it seems like machines running 10.11.6 OS Build 15G31 had an issue when they applied the security update from Oct. 24th. That is when all our MacBook Airs started doing this startup issue. Since upgrading our image to the latest build with all updates and re-imaging MacBook Airs I have not seen the issue.

Seems unlikely as we're seeing the issue on older versions of osx

@allanp81 What other versions besides 10.10.X and 10.11.X are you seeing this on?

@Chuey we've seen it on 10.11.5 and 10.11.3 base images and 10.11.6 that were upgraded from 10.11.5.

@allanp81 I'd create a clean image that is patched and up to date as possible with the system build and re-image the entire machine. That is the only thing I've seen help the issue in my environment on any flavor of 10.11.X

@Chuey Well as per my previous posts, since we firmware upgraded and then reimaged the machines affected we haven't seen a reoccurence and some of the machines have gone 3 weeks without showing the issue.

Its because the hard drive on 2010-2013 Computer doesn't support the latest OS x unless its a Solid State Drive. We was having the same problem and Apple told us to change the hard drive to SSD and we have no more problem.

@Zeek I've had 2012 Mac Minis with SSDs and upgraded RAM get stuck on startup but they had System Build 15G31. Since upgrading them to System Build 15G1108 I've not seen the issue on them. Just my experience though.